1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Berkeley style UIO structures - Alan Cox 1994.
8 #include <linux/kernel.h>
9 #include <linux/thread_info.h>
10 #include <uapi/linux/uio.h>
13 struct pipe_inode_info;
16 void *iov_base; /* and that should *never* hold a userland pointer */
30 struct iov_iter_state {
33 unsigned long nr_segs;
43 const struct iovec *iov;
44 const struct kvec *kvec;
45 const struct bio_vec *bvec;
46 struct xarray *xarray;
47 struct pipe_inode_info *pipe;
50 unsigned long nr_segs;
53 unsigned int start_head;
59 static inline enum iter_type iov_iter_type(const struct iov_iter *i)
64 static inline void iov_iter_save_state(struct iov_iter *iter,
65 struct iov_iter_state *state)
67 state->iov_offset = iter->iov_offset;
68 state->count = iter->count;
69 state->nr_segs = iter->nr_segs;
72 static inline bool iter_is_iovec(const struct iov_iter *i)
74 return iov_iter_type(i) == ITER_IOVEC;
77 static inline bool iov_iter_is_kvec(const struct iov_iter *i)
79 return iov_iter_type(i) == ITER_KVEC;
82 static inline bool iov_iter_is_bvec(const struct iov_iter *i)
84 return iov_iter_type(i) == ITER_BVEC;
87 static inline bool iov_iter_is_pipe(const struct iov_iter *i)
89 return iov_iter_type(i) == ITER_PIPE;
92 static inline bool iov_iter_is_discard(const struct iov_iter *i)
94 return iov_iter_type(i) == ITER_DISCARD;
97 static inline bool iov_iter_is_xarray(const struct iov_iter *i)
99 return iov_iter_type(i) == ITER_XARRAY;
102 static inline unsigned char iov_iter_rw(const struct iov_iter *i)
104 return i->data_source ? WRITE : READ;
108 * Total number of bytes covered by an iovec.
110 * NOTE that it is not safe to use this function until all the iovec's
111 * segment lengths have been validated. Because the individual lengths can
112 * overflow a size_t when added together.
114 static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
119 for (seg = 0; seg < nr_segs; seg++)
120 ret += iov[seg].iov_len;
124 static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
126 return (struct iovec) {
127 .iov_base = iter->iov->iov_base + iter->iov_offset,
128 .iov_len = min(iter->count,
129 iter->iov->iov_len - iter->iov_offset),
133 size_t copy_page_from_iter_atomic(struct page *page, unsigned offset,
134 size_t bytes, struct iov_iter *i);
135 void iov_iter_advance(struct iov_iter *i, size_t bytes);
136 void iov_iter_revert(struct iov_iter *i, size_t bytes);
137 size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t bytes);
138 size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t bytes);
139 size_t iov_iter_single_seg_count(const struct iov_iter *i);
140 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
142 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
145 size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
146 size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
147 size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
149 static __always_inline __must_check
150 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
152 if (unlikely(!check_copy_size(addr, bytes, true)))
155 return _copy_to_iter(addr, bytes, i);
158 static __always_inline __must_check
159 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
161 if (unlikely(!check_copy_size(addr, bytes, false)))
164 return _copy_from_iter(addr, bytes, i);
167 static __always_inline __must_check
168 bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
170 size_t copied = copy_from_iter(addr, bytes, i);
171 if (likely(copied == bytes))
173 iov_iter_revert(i, copied);
177 static __always_inline __must_check
178 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
180 if (unlikely(!check_copy_size(addr, bytes, false)))
183 return _copy_from_iter_nocache(addr, bytes, i);
186 static __always_inline __must_check
187 bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
189 size_t copied = copy_from_iter_nocache(addr, bytes, i);
190 if (likely(copied == bytes))
192 iov_iter_revert(i, copied);
196 #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
198 * Note, users like pmem that depend on the stricter semantics of
199 * copy_from_iter_flushcache() than copy_from_iter_nocache() must check for
200 * IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) before assuming that the
201 * destination is flushed from the cache on return.
203 size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i);
205 #define _copy_from_iter_flushcache _copy_from_iter_nocache
208 #ifdef CONFIG_ARCH_HAS_COPY_MC
209 size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
211 #define _copy_mc_to_iter _copy_to_iter
214 static __always_inline __must_check
215 size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
217 if (unlikely(!check_copy_size(addr, bytes, false)))
220 return _copy_from_iter_flushcache(addr, bytes, i);
223 static __always_inline __must_check
224 size_t copy_mc_to_iter(void *addr, size_t bytes, struct iov_iter *i)
226 if (unlikely(!check_copy_size(addr, bytes, true)))
229 return _copy_mc_to_iter(addr, bytes, i);
232 size_t iov_iter_zero(size_t bytes, struct iov_iter *);
233 unsigned long iov_iter_alignment(const struct iov_iter *i);
234 unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
235 void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov,
236 unsigned long nr_segs, size_t count);
237 void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec,
238 unsigned long nr_segs, size_t count);
239 void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec,
240 unsigned long nr_segs, size_t count);
241 void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe,
243 void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
244 void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray,
245 loff_t start, size_t count);
246 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
247 size_t maxsize, unsigned maxpages, size_t *start);
248 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
249 size_t maxsize, size_t *start);
250 int iov_iter_npages(const struct iov_iter *i, int maxpages);
251 void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state);
253 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
255 static inline size_t iov_iter_count(const struct iov_iter *i)
261 * Cap the iov_iter by given limit; note that the second argument is
262 * *not* the new size - it's upper limit for such. Passing it a value
263 * greater than the amount of data in iov_iter is fine - it'll just do
264 * nothing in that case.
266 static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
269 * count doesn't have to fit in size_t - comparison extends both
270 * operands to u64 here and any value that would be truncated by
271 * conversion in assignement is by definition greater than all
272 * values of size_t, including old i->count.
274 if (i->count > count)
279 * reexpand a previously truncated iterator; count must be no more than how much
282 static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
292 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i);
293 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
295 static __always_inline __must_check
296 bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
297 __wsum *csum, struct iov_iter *i)
299 size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i);
300 if (likely(copied == bytes))
302 iov_iter_revert(i, copied);
305 size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
308 struct iovec *iovec_from_user(const struct iovec __user *uvector,
309 unsigned long nr_segs, unsigned long fast_segs,
310 struct iovec *fast_iov, bool compat);
311 ssize_t import_iovec(int type, const struct iovec __user *uvec,
312 unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
314 ssize_t __import_iovec(int type, const struct iovec __user *uvec,
315 unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
316 struct iov_iter *i, bool compat);
317 int import_single_range(int type, void __user *buf, size_t len,
318 struct iovec *iov, struct iov_iter *i);